A study conducted by a team in the Limburg University in Holland found that when 12 volunteers, familiar with the science behind paper bag rebreathing, “were twice asked to overbreath intensely and then either to rebreath or to restart normal ventilation,” rebreathing returned blood carbon dioxide levels back to normal and cleared symptoms sooner, than when normal breathing was used.

They then conducted a second experiment where the volunteers were asked to do the same thing, but rather than use a paper bag they were asked to use a semiclosed tube system, being told that on both occasions they would be rebreathing.

In reality they actually rebreathed once and breathed fresh air the other time and when the results were checked, the researchers found, even though the carbon dioxide levels recovered quicker when the system was closed i.e. rebreathing, no significant difference was observed in the length of time it took for participants to report that the symptoms had cleared.

This strongly suggests that expectation and belief plays a major part in the success of paper bag rebreathing so whilst the mechanics’ of rebreathing are sound, the mind is far more important when it comes to panic attack sufferers.